1. Field of the Invention
Methods and apparatuses consistent with the present invention relate to content advisory (CA) information on multimedia contents, and more particularly, to generating CA information on contents existing all over the Internet, and using the CA information.
2. Description of the Related Art
From the beginning of the 21st century, the fields of broadband broadcasting and data communication have been rapidly combining. Data communication service providers have competitively entered into the market of broadcasting and are making efforts to cross the boundary between broadcasting and data communication, and broadcasting service providers have been alerted against such occurrences and are making efforts to draw an Internet Protocol (IP)-based broadcasting market into their field.
No matter which side takes the upper hand, one definite fact is that people can now very easily access contents on the Internet, through a television (TV) in a living room. Conventionally, a typical TV is a very conservative device in comparison to a personal computer (PC). In general, a PC is used by an individual while the TV is shared by a whole family. Thus, conventional contents provided by TV broadcasting service providers are produced through self censorship and also viewing age ratings are determined in accordance with strict standards.
However, if Internet Protocol televisions (IPTVs) become popular, content providers will not be restricted to only broadcasting stations and all users using the Internet can provide self-produced contents (for example, user created contents (UCC)). Thus, it is obvious that the amount of contents that could be viewed through the TV will increase exponentially. However, a variety of contents on the Internet are produced without the censorship, and no one is appointed to determine their content advisory (CA) ratings. Accordingly, when IPTVs become popular, a method of blocking harmful contents on the Internet will be regarded as a very important issue. Most existing CA standards have been formed on the basis of a conventional broadcasting environment and thus a new method of providing CA information is required in a new IPTV era.
FIG. 1 is a diagram illustrating a method of transmitting a broadcasting stream according to the Advanced Television Systems Committee (ATSC) standard that is one kind of terrestrial digital TV broadcasting standard.
Referring to FIG. 1, a head-end transmits a transport stream (TS) to a terminal. One TS includes a plurality of elementary streams (ESs). A program map table (PMT) includes information on each service unit (including one or more events) in an ES. A CA descriptor is linked to each PMT and this CA descriptor provides CA information (for example, a parental rating) of an event.
The CA information is preset in the terminal and thus, the terminal determines whether to allow viewing of a content by comparing the CA information included in the CA descriptor of the received TS, and the CA information that is preset in the terminal.
However, a conventional method of providing CA information requires a stream generator and can be applied only to certain types of broadcasting streaming (for example, ATSC streaming). Thus, if a content which exists on the Internet is arbitrarily downloaded and reproduced (for example, an IP-based steaming service), the conventional method may not be applied.
Also, conventional CA information is defined in units of events and thus a PMT has to be continuously updated in order to provide the CA information in more specified units (for example, in units of frames). Accordingly, the system may be prone to overload.